Tunnel Type Sump With Oil Intake Valve Assembly

ABSTRACT

An internal combustion engine is provided with oil intake pipes defining oil inlets on both sides of a tunnel type sump. Each oil intake pipe includes a valve which is operable to close the respective flowpath when the respective sump portion is tilted upwardly about the length axis of the engine. The inlets may be arranged to remain submerged in a minimum quantity of oil which is retained in each sump portion while the engine is tilted through its maximum angular range about both length and width axes.

TECHNICAL FIELD

This disclosure relates to tunnel type sumps for retaining lubricating oil, as used for example on tractor engines, and more generally to oil intake valve arrangements for use in the sump of an internal combustion engine.

BACKGROUND

Agricultural tractors have large wheels to raise the body over soft and uneven ground. In order to ensure stability, it is usual to position the engine as low as possible on the central length axis of the vehicle. However, this is also the optimal position for the driveshaft which transmits power to the rear of the vehicle.

In order to position the engine low over the driveshaft, a tractor engine may be fitted with a tunnel type sump. A tunnel type sump is a sump which is divided into two sump portions on opposite sides of the engine, with a recess, referred to as a transmission tunnel, running axially along the bottom of the engine between the two sump portions to accommodate the driveshaft. The oil pump is arranged to draw oil from separate oil intakes arranged respectively in the two sump portions. Each sump portion may be relatively narrow in the width dimension of the engine.

In use, when the vehicle is tilted about its length axis, for example when traversing sloping ground, oil flowing back to the sump may tend to flow more towards the sump portion on the lower side of the vehicle, so that the operation of the pump transfers oil gradually from the higher sump portion to the lower sump portion. If the level of the oil in the higher sump portion falls below the level of the intake then the pump may draw air through the intake, resulting in undesirable aeration of the oil flow to the moving parts of the engine.

Various valve arrangements have been proposed to exclude air from the lubricating oil drawn from a sump of more common design as used in most internal combustion engines. For example, it is known from FR2196004A5, JPS5893911A, and US6260534B1 to arrange a freely movable valve element or elements to selectively block the flowpaths from oil intakes arranged at opposite ends or opposite sides of a sump.

SUMMARY OF THE DISCLOSURE

Disclosed herein is an internal combustion engine including a plurality of combustion chambers spaced apart along a length axis of the engine, at least one pump, a sump for collecting oil, a first flowpath having a first valve with a first valve element, and a second flowpath having a second valve with a second valve element.

Each flowpath has a respective inlet in the sump and extending from the respective inlet to the at least one pump. The at least one pump is arranged to draw oil from the sump via each of the flowpaths.

Each valve element is biased to an open, rest position in a normal use position of the engine, and movable from the rest position to a closed position to block the respective flowpath by tilting of the engine about its length axis.

The sump is divided into first and second sump portions arranged on opposite, first and second sides of a reference plane containing the length axis and bisecting the engine, the reference plane being vertical in the normal use position of the engine. The inlets of the first and second flowpaths are arranged respectively in the first and second sump portions.

The first valve element is movable from the rest position to the closed position by movement of the first sump portion upwardly in rotation about the length axis relative to the second sump portion. Similarly, the second valve element is movable from the rest position to the closed position by movement of the second sump portion upwardly in rotation about the length axis relative to the first sump portion.

Further features and advantages will be appreciated from the illustrative embodiment which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a tractor with an internal combustion engine in a normal use position;

FIG. 2 shows the engine in its normal use position, in simplified end and side view;

FIG. 3 shows part of an oil intake pipe of the engine including a valve, with the valve body partially cut away to reveal the moving valve element;

FIG. 4 shows the first oil intake pipe in its use position in a first sump portion of the engine (illustrated without oil);

FIG. 5 shows the first sump portion (without oil) with the valve body partially cut away as shown in FIG. 3;

FIG. 6 is a schematic end view of the sump in the normal use position of FIGS. 1-2, with each sump portion containing an equal quantity of oil;

FIG. 7 shows the sump tilted about the length axis of the engine to an intermediate angular position, wherein the first sump portion is raised relative to the second sump portion and contains a minimum quantity of oil;

FIG. 8 is a schematic side view of the sump, showing the first sump portion in the normal use position and containing a quantity of oil equal to that of the second sump portion, as shown in FIG. 6;

FIG. 9 shows the first sump portion in the normal use position and containing the minimum quantity of oil;

FIG. 10 is a schematic section taken in a plane P2 containing the width axis and normal to the length axis, showing the sump in a maximally tilted position about both the length and width axes, wherein the first sump portion contains the minimum quantity of oil; and

FIG. 11 is a schematic side view of the interior of the sump in the position of FIG. 10, looking along the width axis and showing the first sump portion containing the minimum quantity of oil.

Reference numerals and characters which appear in more than one of the figures indicate the same or corresponding parts in each of them.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, a vehicle 1, which may be for example an agricultural tractor as illustrated, is fitted with an internal combustion engine 2 having a plurality of combustion chambers 3 spaced apart along a length axis L of the engine.

Of course, the engine 2 may include air and fuel supply and ignition systems, a crankshaft driven by the pistons, and other usual features which are not shown in detail. The engine may drive the tractor or other vehicle in motion and/or supply power to moving equipment mounted on the vehicle.

The engine 2 includes a tunnel type sump 4 for collecting and storing lubricating oil O. That is to say, the sump 4 is divided by a transmission tunnel 5 into a first sump portion 100 and a second sump portion 200 which are arranged on opposite, first and second sides 101, 201 of a reference plane P1′ containing the length axis L and bisecting the engine. The reference plane P1′ is vertical in the normal use position of the engine, and for ease of understanding a vertical plane P1 containing the length axis L is shown in the drawings; in the normal use position the reference plane P1′ lies in the vertical plane P1. By the normal use position is meant the position of the engine when the vehicle 1 is standing on level ground as shown in FIG. 1. A transmission shaft (not shown) may run through the transmission tunnel 5 to supply power to various equipment mounted on the vehicle.

A width axis W of the engine is defined as normal to the reference plane P1′ and intersects the length axis L mid-way along the length of the sump 4.

Referring also to FIGS. 4 and 5, the two sump portions 100, 200 may extend as shown, generally in parallel in the length direction of the engine on opposite sides of the reference plane P1′ and are upwardly open to receive lubricating oil O which drips down from the rotating shafts 8 and other moving parts of the engine. The two sump portions may form part of a fluidly continuous cavity so that oil falling onto the upper surface 9 of the pan forming the roof of the transmission tunnel may run to either side of the central reference plane P1′ depending on the rotational position of the engine about its length axis L.

Rotation about the length axis L is also referred to as roll, and may occur for example when the vehicle moves along the contour of the land to traverse a slope. Movement up or down a slope will cause rotation about the width axis W, which is also referred to as pitch.

At least one pump 12 is arranged to draw oil O from the sump 4 via each of first and second flowpaths 102, 202 The at least one pump 12 may consist of a single pump 12, and will be referred to for simplicity as the pump. The pump 12 supplies the oil under pressure via outlets 13 to lubricate the moving parts of the engine.

The first flowpath 102 has a first valve 103 with a first valve element 104, while the second flowpath 202 has a second valve 203 with a second valve element 204. Each flowpath extends from a respective, first or second inlet 105, 205 in the sump 4 to the pump 12; the first inlet 105 is arranged in the first sump portion 100, while the second inlet 205 is arranged in the second sump portion 200. Each inlet may be arranged close to the bottom of the respective sump portion and approximately centrally along the length dimension of the respective sump portion, as shown. The inlets may be provided with strainers, not shown.

Referring also to FIGS. 6, 7 and 10, the first valve 103 may be arranged on the first side 101 of the reference plane P1′, and the second valve 203 on the second side 201. Each valve element 104, 204 is biased to an open, rest position in the normal use position of the engine as shown in FIG. 6, and movable from the rest position to a closed position to block the respective flowpath 102, 202 by tilting of the engine 2 about its length axis L.

FIG. 7 shows the engine tilted about the length axis L to an intermediate angular position in which both valve elements 104, 204 remain in the rest position, but any increase in tilt about the length axis L would cause the higher one of the valve elements—which in the illustrated position is the first valve element 104—to move to the closed position. The intermediate angular position is defined by angle α1 between the reference plane P1′ and the vertical plane P1.

FIG. 10 shows the engine tilted about its length axis L to a maximally tilted position, defined by angle α2 between the vertical plane P1 and reference plane P1′. The maximimally tilted position represents one extremity of the maximum angular range through which the engine 2 is designed to be tilted about its length axis L in normal operation.

It will be understood that the opposite extremity of the maximum angular range is defined by an angle α2′ equal to angle α2 on the other side of the vertical plane P1, so the engine can be tilted in either direction about the length axis L. Similarly, the intermediate angular position is defined in each direction from the vertical plane P1 by equal angles α1 and α1′. For ease of understanding, the position which the reference plane P1′ would occupy if the engine were tilted in the direction opposite to that illustrated, to define the angle α1′ or α2′, is indicated as P1″.

Referring to FIG. 11, similarly, the engine 2 is designed to be tilted in normal operation through a maximum angular range in either direction about its width axis W. The maximum angular range is defined between equal angles α3 and α3′ between the length axis L and a horizontal line H lying in the vertical plane P1 and passing through the point of intersection of the length and width axes L, W. In FIG. 11 the engine is tilted to the maximally tilted position defined by angle α3; the opposite angle α3′ is defined by the position L′ which the length axis L would occupy if tilted in the other direction.

Because of the direction of the view along the width axis W of the tilted engine, the width dimension of the horizontal surface plane of the body of oil O can be seen in FIG. 11, which is not the case in the other figures. Despite the maximally tilted position of the engine 2 about both axes L, W as shown in FIG. 11 it can be seen that the first inlet 105 on the raised side of the sump remains submerged in the oil, as does the second inlet 205 on the lower side of the sump, as further discussed below.

The maximum angular range for normal operation of the engine may be defined by the maximum ground slope angle on which the machine may work. Thus, the maximum angular range may permit a relatively larger maximum tilt angle in roll or in pitch only (if the machine is facing in a direction aligned with, or normal to, the slope angle) equal to the maximum ground slope angle, and a relatively smaller, equal maximum tilt angle simultaneously in both roll and pitch (if the machine is facing at 45° azimuth relative to the slope angle). By way of example, the maximally tilted position in either angular direction away from the normal use position, simultaneously both in roll and in pitch, may be defined by a tilt angle α2, α2′, α3 or α3′ of about 17°, 21°, 24° or even more, corresponding respectively to a maximum ground slope angle of about 25°, 30°, 35° or even more.

Referring to FIGS. 3-6, each flowpath 102, 202 may be defined as shown by a respective oil intake pipe 107, 207 having a riser portion 106, 206 which extends downwardly into the respective sump portion 100, 200 towards the respective inlet 105, 205. (That is to say, downwardly in the normal use position of the engine, when considered in the direction of the flowpath towards the inlet).

Each valve 103, 203 may be arranged in the flowpath 102, 202 between the pump 12 and the riser portion 106, 206 of the respective pipe. Although only the first oil intake pipe 107 can be seen in FIGS. 4 and 5, it should be understood that the second oil intake pipe 207 is similarly arranged on the other side of the reference plane P1′.

As best seen in FIG. 3, each valve element 104, 204 may be a ball, and may be movably retained within a valve body 108, 208 which extends downwardly away from the pump 12 towards the riser portion 106, 206, defining an axis X which slopes downwardly away from the reference plane P1′ in the normal use position of the engine, and along which the valve element 104, 204 can move between the open and closed positions.

The balls or other valve elements 104, 204 may be biased to the rest position by gravity. In the illustrated example, each valve element 104, 204 is a heavy ball which is free to move along the axis X between a valve seat 14 and a retainer 15 which together with the valve body 108, 208 define a cage containing the ball. The ball sealingly engages the valve seat to block the flow of oil to the pump in the closed position of the valve; in the open position, the ball may rest against the retainer which allows oil to flow around the ball and through the valve seat. For simplicity the valve body is illustrated as a portion of the oil intake pipe 107, 207, but it may include suitable fittings to facilitate assembly. As shown, the valve seat 14 may be located between the reference plane P1′ and the respective valve element 104, 204.

Referring again to FIGS. 6, 7 and 10, the first valve element 104 is movable from the rest position (shown in FIGS. 6 and 7) to the closed position (shown in FIG. 10) by movement of the first sump portion 100 upwardly in rotation about the length axis L relative to the second sump portion 200, beyond the intermediate angular position of FIG. 7 towards the maximally tilted position of FIG. 10.

Similarly, although not illustrated, the second valve element 204 is movable from the rest position to the closed position by movement of the second sump portion 200 upwardly in rotation about the length axis L relative to the first sump portion 100.

The engine 2 is configured to retain a recommended quantity of oil O, as shown in each of FIGS. 6-11.

Each inlet 105, 205 may be configured, when the recommended quantity of oil is retained in the engine, to remain submerged in the oil O at all times during normal use of the engine 2 while the engine is tilted through the maximum angular range, simultaneously about the length axis L and about the width axis W. That is to say, both inlets 105, 205 may remain submerged in the oil O when the engine is tilted to its maximum allowable angle, at the same time both in roll and in pitch, as shown in FIG. 11.

To achieve this, each of the first and second sump portions 100, 200 may be configured so that, when the recommended quantity of oil O is retained in the engine as shown, the respective sump portion 100, 200 will retain at least a minimum quantity of that oil O at all times during normal use of the engine 2 while the engine is tilted to the intermediate angular position (FIG. 7) about the length axis L, and simultaneously through the maximum angular range (i.e. to the maximally tilted position) about the width axis W.

This ensures that at the moment that roll increases beyond the intermediate angular position, causing the respective valve 103 or 203 to close, further operation of the engine in that position will not reduce the quantity of oil in the respective, raised one of the sump portions below the predefined minimum quantity.

The intermediate angular position is defined by the configuration of the valves 103, 203. For example, by increasing the slope angle of the axis X the valve 103, 203 may be arranged to close at a larger tilt angle of the engine.

The configuration of the sump portions can be determined by testing to satisfy the above mentioned criterion. In practice this will depend on numerous points of detail as well known in the art, including the length, width and depth dimensions of the respective sump portions, the height of the transmission tunnel, and the layout of the internal surfaces of the engine block and moving parts which define the routes by which oil returns to the sump in different angular positions of the engine, as well as the recommended quantity of oil to be retained in the engine.

The minimum quantity of oil which remains in each sump portion 100, 200 at the moment the respective valve 103 or 203 is closed may be selected to ensure that each inlet 105, 205 will remain submerged in that minimum quantity of oil at all times during normal use of the engine while the engine 2 is tilted through its maximum angular range, both in roll and in pitch.

That is to say, when at least the minimum quantity of oil O is retained in each sump portion 100, 200, each inlet 105, 205 is configured to remain submerged at all times during normal use of the engine while the engine is tilted through its maximum angular range (α2-α2′; α3-α3′), simultaneously about the width axis W and beyond the intermediate angular position about the length axis L. Since the inlet remains submerged, the riser portion 106, 206 of the oil intake pipe does not drain into the sump while the valve 103, 203 remains closed, and so when the valve opens again no air is drawn into the pump 12.

INDUSTRIAL APPLICABILITY

In order to respond to tilting about the length axis L, the axis X of movement of the valve element 104, 204 may be arranged as shown to extend downwardly away from the reference plane P1′ against the direction of flow in the respective flowpath 102, 202. This requires that the valve 103, 203 is mounted in a position where there is enough room to accommodate the axial length dimension of the valve mechanism.

The novel valve arrangement may be employed to prevent aeration of the oil flow drawn from a tunnel sump, even where each sump portion 100, 200 is too narrow to accommodate the valve body 108, 208 near the bottom of the sump in an orientation to enable the valve element to respond to movement of the engine in rotation about its length axis L. In such arrangements, each of the valves 103, 203 may be positioned at an elevated level above the bottom of the respective sump portion 100, 200 as shown, with a riser portion 106, 206 of the oil intake pipe extending downwardly into the sump between the valve 103, 203 and the inlet 105, 205.

In order to ensure that the riser portion 106, 206 remains full of oil, thus preventing air from entering the riser portion while the respective valve 103, 203 is closed and subsequently being drawn into the pump 12 when the valve opens again, the recommended quantity of oil O in the engine may be selected, in combination with the configuration of the sump 4 and the inlets 105, 205, to ensure that each inlet 105, 205 remains submerged in the oil O at all times while the engine is in normal operation and tilted in any direction through its maximum angular range about its length and width axes L, W.

More particularly, each sump portion 100, 200 may be configured to retain at least a minimum quantity of the oil O at all times while the engine is tilted through its maximum angular range about the width axis W, and about its length axis L up to the intermediate angular position beyond which further tilting would cause one of the valves 105, 205 to close. This ensures that when the respective valve closes, each sump portion 100, 200 will contain at least the minimum quantity of oil. In this arrangement, the inlets 105, 205 are configured to remain submerged in the oil O, as long as the minimum quantity of oil is present, while the engine 2 tilts through its maximum angular range about both axes L, W. Thus, while further tilting closes the valve 103, 203 of the sump portion on the raised side of the engine, the retained minimum quantity of oil O is sufficient to prevent air from entering the inlet, and so to prevent empting of the riser portion 106, 206 of the pipe.

In this way a valve may be arranged in a raised position above the bottom of the sump and yet still prevent air from entering the open, riser portion 106, 206 of the oil intake pipe that extends down from the valve 103, 203 to the bottom of the sump.

A raised valve position may also magnify small angular movements of the vehicle 1, resulting in a faster response to changes in ground angle.

In summary, in embodiments, an internal combustion engine is provided with oil intake pipes 107, 207 defining oil inlets 105, 205 on both sides of a tunnel type sump 4. Each oil intake pipe 107, 207 includes a valve 103, 203 which is operable to close the respective flowpath 102, 202 when the respective sump portion 100, 200 is tilted upwardly about the length axis L of the engine. The inlets 105, 205 may be arranged to remain submerged in a minimum quantity of oil O which is retained in each sump portion 100, 200 while the engine 2 is tilted through its maximum angular range about both length and width axes L, W.

Many adaptations are possible within the scope of the claims.

In the claims, reference numerals and characters are provided in parentheses, purely for ease of reference, and are not to be construed as limiting features. 

1. An internal combustion engine including: a plurality of combustion chambers spaced apart along a length axis of the engine, at least one pump, a sump for collecting oil, a first flowpath having a first valve with a first valve element, and a second flowpath having a second valve with a second valve element; each flowpath having a respective inlet in the sump and extending from the respective inlet to the at least one pump; the at least one pump being arranged to draw oil from the sump via each of the floe paths; each valve element being biased to an open, rest position in a normal use position of the engine, and movable from the rest position to a closed position to block the respective flowpath by tilting of the engine about its length axis; wherein the sump is divided into first and second sump portions arranged on opposite, first and second sides of a reference plane containing the length axis and bisecting the engine, the reference plane being vertical in the normal use position of the engine; the inlets of the first and second flowpaths are arranged respectively in the first and second sump portions; the first valve element is movable from the rest position to the closed position by movement of the first sump portion upwardly in rotation about the length axis relative to the second sump portion; and the second valve element is movable from the rest position to the closed position by movement of the second sump portion upwardly in rotation about the length axis relative to the first sump portion.
 2. An internal combustion engine according to claim 1, wherein the first valve is arranged on the first side of the reference plane, and the second valve is arranged on the second side of the reference plane.
 3. An internal combustion engine according to claim 1, wherein each flowpath is defined by a respective pipe having a riser portion which extends downwardly into the respective sump portion towards the respective inlet.
 4. An internal combustion engine according to claim 3, wherein each valve is arranged in the flowpath between the at least one pump and the riser portion of the respective pipe.
 5. An internal combustion engine according to claim 4, wherein each valve element is movably retained within a valve body, the valve body extending downwardly away from the at least one pump towards the riser portion.
 6. An internal combustion engine according to claim 5, wherein each valve element is a ball.
 7. An internal combustion engine according to claim 4, wherein the engine is configured to retain a recommended quantity of oil, and each inlet is configured, when the recommended quantity of oil is retained in the engine, to remain submerged in the oil at all times during normal use of the engine while the engine is tilted through a maximum angular range, simultaneously about the length axis and about a width axis intersecting the length axis and normal to the reference plane.
 8. An internal combustion engine according to claim 4, wherein: the engine is configured to retain a recommended quantity of oil; and each of the first and second sump portions is configured, when the recommended quantity of oil is retained in the engine, to retain at least a minimum quantity of said oil in the respective sump portion at all times during normal use of the engine while the engine is tilted: about the length axis to an intermediate angular position beyond which any increase in tilt about the length axis would cause the first or second valve element to move to the closed position, and simultaneously through a maximum angular range about a width axis intersecting the length axis and normal to the reference plane; and each inlet is configured, when at least said minimum quantity of oil is retained in each sump portion, to remain submerged in the oil at all times during normal use of the engine while the engine is tilted through a maximum angular range, simultaneously about the width axis and beyond said intermediate angular position about the length axis. 